This Tip Sheet was updated in 2007. You will be redirected to the new page in 5 seconds.

If this page does not redirect, click here.

Tip Sheet: What Do We Know About Hurricane Prediction, Behavior, and Impacts?

September 7, 2005

BOULDER—Tropical Storm Nate became the 14th named storm of the season on September 5, continuing the unprecedented pace of the 2005 Atlantic hurricane season. In this record-breaking year, where will the next research breakthroughs in hurricane forecasting, tracking, and impacts come from?

Below are details on hurricane-related efforts at the National Center for Atmospheric Research (NCAR) and its parent organization, the University Corporation for Atmospheric Research (UCAR), as well as two visuals to illustrate your hurricane stories.

Experts are available to describe

• hurricane-related deaths in the near term and long after the storm
• how hurricanes spin up and gain or lose strength (intensity)
• how even weak tropical storms and hurricanes can lead to devastating floods
• how a warming planet may be augmenting hurricane strength

How strong will it get? Research on hurricane intensification

A multiagency team of researchers flew near Hurricanes Katrina and Rita and continues to gather data from coordinated flights over the Atlantic to examine how swirling rainbands may help hurricanes gain strength. Follow these links to learn more about the RAINEX field experiment:

• NCAR News Release: Rita and Beyond: Research Model Advances Hurricane Intensity Prediction (September 21, 2005)
• NSF News Release: Hurricane Katrina: Scientists Fly Into Eye of the Storm (August 30, 2005)
• NCAR News Release: Radar Probes Hurricane Rainbands (August 8, 2005)
  

Recent studies with computer models support a premise long held by some climate scientists: with warmer sea-surface temperatures and moister air, more energy goes into the showers and thunderstorms that feed hurricanes, pushing more of them into the extreme category. Follow these links for research news on the relationship between hurricanes and global warming:

• NCAR News Release: Hurricanes Are Getting Stronger, Study Says (September 15, 2005)
• MIT news release: Hurricanes growing fiercer with global warming (July 31, 2005)
• NCAR news release: Hurricanes To Intensify as Earth Warms (June 16, 2005)

Hurricane basics

What's the difference between a hurricane and a tropical cyclone? What wind speed correlates with each hurricane category? Follow this link for a feature story offering hurricane basics and a research roundup with numerous links to resources within and beyond NCAR and UCAR:

• Feature story: Hurricanes—Keeping an eye on weather's biggest bullies (September 2005)

Christopher Davis
Scientist, Mesoscale and Microscale Meteorology Division and Research Applications Laboratory, NCAR
303-497-8990
cdavis@ucar.edu
Specialties include thunderstorms, squall lines, tropical cyclones, hurricanes, coastal storms

Chris Davis studies the systems that lead to thunderstorms and other heavy rainfall events, including squall lines, tropical cyclones, and hurricanes. He uses observations and sophisticated computer models such as the NCAR/Penn State Mesoscale Model, version 5 (MM5), to construct a basic understanding of the evolution of these systems. Other interests include the rapid intensification of nontropical coastal storms and the effects of mountains on midlatitude storm systems.

Greg Holland
Senior Scientist, Mesoscale and Microscale Meteorology Division, NCAR
303-497-8949
gholland@ucar.edu
Specialties include hurricane structure and behavior

Greg Holland is director of NCAR's division studying weather on the local and regional scale, MMM. His background is in tropical meteorology and severe weather, with a strong emphasis on tropical cyclones and hurricanes. Before coming to NCAR he employed his expertise in robotic aircraft, also known as unmanned aerial vehicles (UAV), as director of the company Aerosonde. Holland spent 22 years as a forecaster, lecturer, and research scientist at the Bureau of Meteorology Research Centre in his native Australia.

Ilan Kelman
Visiting Scientist, Center for Capacity Building, NCAR
303-497-8122
ilan@ucar.edu
Specialties include disaster impacts (people, communities, built environment), vulnerability of islands, disaster diplomacy

Matthew Kelsch
Hydrometeorologist, Cooperative Program for Operational Meteorology, Education and Training, UCAR Office of Programs
303-497-8309
kelsch@ucar.edu
Specialties include floods: post-hurricane, urban, flash

Wen-Chau Lee
NCAR RAINEX home page
Scientist, Earth Observing Laboratory, NCAR
303-497-8814
wenchau@ucar.edu
Specialties include hurricane and tornado winds, hurricane intensity

Wen-Chau Lee is the chief scientist for NCAR's ELDORA Doppler radar, which flies on the tail of a P-3 research aircraft operated by the Naval Research Laboratory. ELDORA captures detailed images of precipitation and winds produced by hurricanes and severe thunderstorms. Lee has also developed a mathematical technique to pull more information out of ground-based radar depictions of intense, fast-changing weather systems, including hurricane eyewalls.

Kevin Trenberth
Senior Scientist, Climate and Global Dynamics Division, NCAR
303-497-1318
trenbert@ucar.ed
Specialties include global warming and its influence on the water cycle (rain and snow, drought, hurricanes); El Niño

Kevin Trenberth heads the Climate Analysis Section of NCAR's division dedicated to understanding Earth's climate system, CGD. His main interests are climate variability and El Niño, global climate change, the hydrological cycle, and climate observations. His research emphasizes the analysis of observational data to understand what happens in the real world. Trenberth has been involved for many years in the Intergovernmental Panel on Climate Change, serving as a convening lead author and lead author for the IPCC Scientific Assessments of Climate Change. Trenberth received the Jule G. Charney award from the American Meteorological Society in 2000 and is a fellow of the AMS, the American Association for the Advancement of Science, and the New Zealand Royal Society.

Eyeing Katrina The peak winds of over 100 miles per hour that buffeted New Orleans during Hurricane Katrina could have been much worse had the storm made landfall at a different moment in the cycle of its eyewall. Long-lived, intense hurricanes often go through an eyewall replacement cycle that takes a day or so to complete. The result is collapse of the main eyewall and temporary weakening of the storm. Then an outer eyewall contracts and takes its place, allowing for restrengthening. Katrina appears to have been going through the weaker stage as it approached land. The two top images capture Katrina with an intact eyewall at 5:45 p.m. Eastern Daylight Time on Sunday, August 28, as it moved over warm water in the Gulf of Mexico. By 5:45 a.m. on Monday, the weakened eyewall is being further disrupted by interaction with the land surface. Click on each image to enlarge it. (Unidata GEMPAK images by Jeff Weber, UCAR; data from water vapor and infrared bands of NOAA GOES-E satellite.)

The National Center for Atmospheric Research and UCAR Office of Programs are operated by UCAR under the sponsorship of the National Science Foundation and other agencies. Opinions, findings, conclusions, or recommendations expressed in this publication do not necessarily reflect the views of any of UCAR's sponsors.